When a frame structure is excited by a horizontal external force, the girders starts to displace horizontally. If such displacements are large or if they occur periodically they may have serious impact on the conditions of the structure and may cause severe damages or even result in a collapse.
Dampers play an important role in the protection of structures such as buildings, and they exist in numerous variants. Dampers are typically damping the motion by means of a frictional force between two moving parts attached to the frame structure of the building or by means of a fluid being pressed to flow between two chambers through a restricted tube. Other similar well-known methods of damping motion or vibrations exist. Some dampers are actively changing the damping effect corresponding to external conditions, and other dampers are passive dampers having a constant damping characteristic. Typical dampers are costly to produce and even more costly to assemble into a structural frame of a building. Typically a building have to be designed for a specific damper, either due to the bulky design of the existing dampers or due to correlation between the structural characteristics of the damper versus the characteristics of the building.
U.S. Pat. No. 4,409,765 (Pall) Relates to a building having a pair of structural elements with a member connecting these structural elements and where the member has a slip joint with frictional surfaces. The slip joint furthermore has clamping means for forcing the frictional surfaces together. The patent does not disclose a rotational hinge like assembly of the damper, providing a rotational friction.